A lot of mobile carriers are moving away from completely unlimited data plans, but starting on September 5, T-Mobile, the No. 4 U.S. carrier, will begin offering data plans that have full-speed service, no matter how much data is used. While it does sell some plans that are considered “unlimited” already, the speed slows down once a user reaches a preset limit.

For its upcoming unlimited data plan option, T-Mobile will charge $20 to $30 a month extra on top of a voice and texting plan. So a single line “value” plan with unlimited talk, text, and data will be $69.99. A similar traditional plan, with a subsidized phone price, will cost $89.99 a month.

These plans are actually $5 cheaper a month than what T-Mobile charges for current plans that slow down after 5GB of high-speed data is used. These plans, however, can be used on your phone, even when it’s acting as a mobile hotspot or attached to a computer, unlike the new plans.

The new plans from T-Mobile are the carrier’s latest effort to retain customers. The company is also working towards allowing users to bring an iPhone onto its network at full data speeds.

While T-Mobile doesn’t currently sell the iPhone, it has more than 1 million iPhones running on its network. The downside is that the current limitations means that those iPhones on the network only get data at slow 2G speeds.

T-Mobile is aiming to get iPhones running at full speed later this year and is working on a big rebranding campaign, which is planned for the second half of the year.